This wonderful amateur footage show two Hobbies chasing a Swift. The Hobbies bank and stoop, accelerating into G-force turns, the wingbeats deep and elastic, the tail ruddering. Repeatedly, they swing under and up at the Swifts, attacking from beneath so that their target is silhouetted against the sky.
You can read the whole feature in the October 2011 edition of Bird Watching magazine
This video was posted on YouTube by betacygni
